With a color photographic material the image is formed by subjecting the material to an exposure to light and then carrying out color development wherein the couplers react with the oxidized primary aromatic amine based developing agent. In such a system the reproduction of colors is achieved using the subtractive color method with the formation of yellow, magenta and cyan colored images which have a complementary relationship for the reproduction of blue, green and red.
The basic requirements of each coupler are not only that it should form a single color but it should also have various desirable characteristics such as the formation of a dye which has excellent spectral absorption characteristics, a high rate of dye formation, a high color forming density and the formation of a dye which is very fast with respect to light, heat and moisture. Today, in particular, when there is a demand for high photographic speeds and higher picture quality from photosensitive materials there is a strong demand for the development of couplers wherein the rate of dye formation is high and the color forming density is high. Moreover, the properties mentioned above are very important requirements when designing DIR couplers (these are couplers which release a development inhibitor on reaction with the oxidized form of a primary aromatic amine developing agent and they are used with a view to improving picture quality in terms of sharpness and color reproduction).
The introduction of highly polar groups, and especially sulfonamido groups or sulfamoyl groups, into the coupler molecule is one effective means of increasing the rate of dye formation, and such couplers have been disclosed, for example, in JP-A-52-115219, JP-A-54-48541, JP-A-63-201655, JP-B-2-13777, U.S. Pat. Nos. 4,525,450 and 4,356,258. (The term "JP-A" as used herein signifies an "unexamined published Japanese patent application", and the term "JP-B" as used herein signifies an "examined Japanese patent publication".) The introduction of an acidic leaving group into the coupler is another effective means and examples of this include the introduction of p-hydroxybenzenesulfonyl group or p-hydroxybenzenesulfinyl group as disclosed in U.S. Pat. No. 4,443,536 and the introduction of N-acylsulfamoyl group as disclosed in British Patent 909,318, JP-B-62-61251 and U.S. Pat. No. 4,617,256. However, these couplers have a disadvantage in that the fastness of the colored image deteriorates as the rate of dye formation is increased, and further improvement is desirable.